I..' \'. J. Gupra and H. h. Erben Palaont. 2. 57 1!2 4 Abh. 1 133-1 lC Sruttgart, Juni 1983
Literature
I:il,.glri o\\h>. Ii I I 1971 I.L)r\on\Llr Ammonoldea. 11. Goniariri. - Tmdx Paleonr. Inst. Akad. Nauk 555li. 127. 225 pp , 19 11; tcxfils\.: Lloskra. HOC.
Taxonomic remarks
The iorms allied to the genus Pzctonza BAYLE,1878 (with thesubgenera P~cton~as. str., Trio- zires Bucn.\~,n,1924, \'inalesphincter SPATH,193 I, and Pachypictonia SCHNEJD,194C) arc me- dium-sized to large, moderately to strongly erolure perisphinctids of rounded to compressed whorl section and body chamber lengths of up to one whorl. Their ribbing is strong. Pictonia s. srr. (type species:Pictonaa baylei SALFELD,1913) has a depressed to round whorl section, and ribbing intermediate in character betreen perisphinctoid and rasenioid, i. e. strong primaries, each of which branches into 2 or 3 secondaries or intercalatory ribs. Each whorl slioar 3 or 4 more or less pronounced constrictions.Pictonia s. str. n~aspreviouslyknown from thr Uppermost Oxfordian and Lonrer Kimmeridgian of Korrhwestern and Central Europe (up- pw part of ldoceras planula zone till Ataxioce~achypseloqcium zone). Trioziter (rvpc specles: Triozitessemtnudatirs BUC~MAN,1924) is a large form which bears di- stant triplicate rib?. Conspicuous on the inner whorls, the ribs grow fainter and fadeaaay con>- plctrl!. before the beginning ot the body chamber. This poorly knonn subgenus has been men- t~onedtrom the Lower Kinlnleridfiian of Greenland and England. \'inalesphinctes (typespecies: \'inaiesphinctes roig~SPATH, 1931), perhaps best to be grouped together xvlth Triozites, has likewise alarge shell and a body chambernrith lacking or very feeble ornamentation. According to JUDOLEY8: FURRAZOLA-BERMUDEZ(1968: 103-107) each whorl has between 3 and 5 constrictions. The inner whorls are ornamented with fine to somewhat coarser peri~~hinctoidribbing, with bipartite rib units and external intercalatory ribs. This sub- genus has been described as an endemic group from the Cuban Upper Oxfordian. There are doubtless morphological affinities betnyeen those species of the subgenus which display finer ribbing, and the Denpia-Pomeranta group. The same is true for the species with coarser orna- mentatlon with respect to Pachypictonia. I'ach?;oictonta (type species: Pach?pictonaa dacquei WEGELE, 1929; see GEYER 1961: 116-123) has, in its typical forms, coarse nodiform to cuneiform primaries, most of which branch Into two secondaries and an additional inrercalatory rib. On the body chamber appear characteristic stuffed ribs. Constrictions are seldom to be observed. Frequently the shells are large. This subgenus has previously been described from the Franconian, and more rarely, Swa- bian Lower Kimmeridgian (Sutneru platynota zone and Ataxioceras hypselocyclum zone). SALFELD(1917: 70-73), ARKELL(1937: 45), SCHNEID(1940: 79-81), GEYER(1961: 114-1 18, 124-116) and EXAY(1966: 550-554) hare drawn attention to the difficulty presented by the set- ting of taxonomic delimitation within the Pictoniinae. With regard to the differing conceptions we refer ro these works. Taxonomical observation by 0. F. GEYER:In my publication on the Perisphinctidae from the Southern German Lower Kimmeridgian (1961) I was as yet uncertain about the taxonomical location and rank of Pomerania and Pachypictonia. In my monography I considered the genus Pomerania (with the subgenus Pachypictonia) pro\-isionally on a par with the genera Pictonia and Ringsteadia, on the other hand, I assigned to the latter the subgenera tineta DOHM,1925, and Decipta ARKELL,1937. Today, 20 years later, I would still consider Deapia a subgenus of the genus Rzngsteadia, as long as the so-called ,>megagenera. with many subgenera, are to be preferred to a large number of taxonomic ,>minigenera<<-in other words, if one does not wish to carry taxonomic splitting too far. This holds especially true in the case of unclear taxonomic re- I IK. I.(;fl'~rapl>~c inti xrc,logic setring of the localities "Arroyo de 10s Molinos" (A) and "La Almola" (B) lationships. On the other hand, today I wish to follow my colleagueR. ENAY(Lyon) in conside- lri \oull~ern\pa111 1 CRCII~A: I = Aljibe unit, 2 = Algeciras unit, 3 = Bolonia unit, 4 = diverse units (Al- I~IAILIIJI. 'I rrtqil~ taxonomic understanding which cannot be bound by rules. W'hen SCHNEID(1940) describes 39 "species" ofPlctonia, 35 of which are new, and bases this wealth of names upon a total of 55 spe- cimens from the Franconian UpperJurassic, many a revising author is sure to have problems fol- lowing this wilful "taxonomia tranconica" (which has found its adepts). Description of the specimens Pictonia (Pacb~pictonia)perornuzwla SCHNEID,1940 Fig. 2, 3A. 4A \. 194C Plcro~~rapnontatr~l;. - SCHSEID:p. 84, PI., 5, fig. f (? fig. 5 . \ 1942 P~nonmcr/nt?. - SCHXEID:p 86, pl. 5, ~g 6 (: pl 6, t~q.l I. v. 1961 Po~nrrdnraiPacI~~prnonla. prror~~atnla. - GEYER:p. 121,.~l.21, iig. 3. rest-figs. 137: 2nd 145. >laterial: A single specimen: I-'. AG,.R (Depto. Paleont. Granada). Local i t y : "?\rroyo de 10s >lolinos"; topographic sheet of Tarifa: 36'5'4)C" N - 1'54'2 I " \Y'. Grological setting: .4 Jurassic klippe in the allochthonous Flyssh Complex o( "C~n~poJc Gibraltar". Type horizon: Uncertain, loose specimen. The shell of the cpecimen (SP)has adiameter (D) of 152 mm. The body chamber takec up np- proximately all of the last whorl. Fig. 3A shows the urhorl section, oi rather steep unlbilical slope, the only slightly curved flanks and the like.u.ise lightly curved to flattened external area. The phragmocone displays strong priman. ribs with nodous thickening on the umbilical edge, and hiplicate to triplicate branching (Fig. 4A). This ornamentation gives way to much less pro- minent, simple ribs after the first quarter of the body chamber. The shell dimensions and num. her of rihs oi our specimen (SP) as well as those of the holotype quoted in the synonym list (H) and those of GEYER'Ssynype (S) are: D width of whorl height number of umbilicus primary ribsfwhorl SP 150 mm 36.C 27.5 15 S 145 mm 14.C 31.0 26 SP 130 mm 45.5 26.5 21 H 120 mm 47.0 28.0 27 SP 100 mm 42.C 32.0 20 H 80 mm 2 1 Picronia ~Pac/?ypictonia)cf.peregvinariu SCHXEID,1940 Fig. 3B, 4B v'~1940 PJC~~II~Jprrr,yrr?ldri,r. - SCHXEID:p. 82, pi. 5, fig. 3. !Vf,I I'r,~rrrranr~a(l'ar/~~prnonra pcrornarul (partim). - GESER:p. 122 (non fig.). 51 21rr1al : .4 \ingle \prilmrn; F.AM.30 fDepto. Paleont. Granada). I #,< rl ~t\.: "1.1 Almc>la": topographic sheet of Ronda; 5"8'45" N - 36"40'30" W. (,r .4s differences to the helot!-pe oi Pictoriia peregvtnu~iaa-e may mention the loner rare of branching (holot! pe: approximate 3.8 per whorl) and the primaries which are hardly thickened at all. GEYER(1961) joined the speciesPicronzaperegrinaru toPzctotiiaperort7ati1la~One species is hardly distinguishable from the other- as in man!- other cases of the Pictoniids- as soon as one allows for a minimum of variabillry. As, however, one only has single specimens to a-ork with, it is best to assign these to previously described and illustrated "species". The find and results lose no significance rhereb>-. On the age of the specimens Due to the circumstances of the discovery, an accurate and direct biostratigraph!. of the spe- cimens is difficult. F.AG,.R is a loose specimen from an outcrop in which the b~ostratigra~hi- cally representative fauna is: level 20 - H)bonoticeraspressuiuni presswlum ~~EUMAYR),Hybotroticera~pressu~~~n i.eresfOiCum (HER- BICH),TarameNiccras sp. ex gr. compsum (OPPEL),Vzrgalrthacoceras sp., Aspidoceras rafaeli (OPPEL). level Y - Garnierrspilinnes sp.. .4spidocerar ixhlandi (OFPEL),Aspidocems sp, ex gr lo,zgispinum (So- VERB) ). ie\ ei S - ZPbrodites sp. aft, grecoi (CAKA~ARI),illeiosimoceras tfe1.e~(I\TEuMA~R), ri!es~s~vz~~~era~ herbi- CAI YO^ HAUER),Crussoli~~ras dit,zswnl (QUENSTEDT),Garnrerisphinctes sp, ex gr. champion- neti (FOKTANNES). level 19 - .4rprdoceras sp. ex r longispinurn (Sou~~~s~),,4spidocerasacanthrcum (OPPEL),Orihaspidoce- ras sp. ex gr. schilki (OFFEL). le\.el 18 - Physodoceras sp. ex gr. contcmporaneun~(FAVRE). Fig. 3. Whorl sections. A = hctonur (Pa~h~prcronialperornatula;above: diameterappros. iiinlrn, bcliju.: Unfortunately, no fauna is found in this profile below level 18, whose exact biostratigraphi- diameter approx. 125 mm. B = Pictonza (Pachyprnonia, cf.peregnnaria; above: diameter approx. 145 mrn, cai location is uncertain. In the level X theDivisi~mzone is clearly developed. Between both, the below: diameter approx. 115 mm. level 19 without common A'ebrodites and Mesosimoceras, and without Crussoliceras, perhaps belongs to the upper part of rheStro~nLeckizone (see OLORIZ1978). With rhe present data the complete recognition of the Lower Iiimmeridgian is not possible. Onthe other hand, F.AM.30 comes from a bank, 1 m thick approximately without innerdif- ierentiated layering and from which several significanr biostratigraphic species hare been collec- ted: Taramellreeras sp. ex gr. cotnprum (OPPEL),Taramell~ceraspugrlepu~iiordes (C~s~v~~~),Aspcdoceras Iongispinum (SOVERBY),Physodoce~-as aitenense (D'ORBIGNI-),Pl>ysodoreras conremporaneum (FAVRE), Orthaspidoceras liparum (OPPEL),Orthaspidoceras schilleri (OPPEL),Pseudowaagenu sesqu~nodosum (FONTANXES),Meroszmoceras herbrchi (vos HAUER),Cr~ssoliceras sp., Garnierisphznctes sp. ex gr. champronnetti (FONTANNES),Hybotioficerrls pressuluni (NEUMAIR),Torquatisphinctes sp. and Pachy- sphrnctes sp. ex gr. grandt~(SPATH) mareller (COLLIGNOY). With this fauna, apart from Di~lsumzone, the bi~strarigra~hicalaccuracy in the rest of the Lower Kinimeridgian is nor possible. Again, thr impoqsibilit!- to recognize internal differential horizons has increased the uncertainty as to the precise bi~stratigra~hiclevel of the specimen. .4ccording to all this, the only one possible approximation, at present, is the one deril-ed from the proposed taxonomy. P~cton~ape~omarirl~~,Pictoninperegrlnana and allied forms occur in the sourhern German Jurassic in the older Loner Kimmeridgian (Swineria piatynota zone, ? Ataxioceras hJpseloqclum zone). The entire subgenus Pachyprctonia occurs in the same area from the highest Oxfordian (Srrtnena subzone) up to rhr Lon-er Kimmeridgian (Ataxioce- ras l~ypse!oqclum zone); see GEYER(1961: 118). It appears, however, thatPaci7)prctonia reaches the fiatrolzcevas dr;iswm zone in the French Jurassic (ENAY1980: 588). Therefore an older Lower Kimmeridgian age could be assumed to be fair]!- certain for rhe ta-o Spanish specimens. 1 IG 4 \I~~CII~.II~LKr.~ph\ ot the r~hhlng.A = Picronia fPachypictonia)perornatula:diameter approx. 8C cm. Nevertheless, neither of the Spaniali profiles provides any indication of the existence of the I\ /'icr Historischer Uberblick 1842 D'ORBIGKYsrellt die Art Amrnonitesproteus aus dem Alb van Clars (Escragnolles, SE-Frank- reich) auf. IS77 GABBbeschreibt Ammon~iesvenian~llenas aus dem Alb von Parietambo (Peru), halt ihn aber fur un- rerjurasslsch. IS81 STEINMANYbegriindet die Gattung Mojsiso-ircria mit der Typusan M. difeld~ STEIKMAKN1881. 1882 STEINMASKnimmt in einem Nachrrag zu GABBStellung und sagr bezuglich Amm. -ientan~Ilensis: .Als Tvpus des GABB'schen Ammonites \'entanillensis mu13 man die Bruchstucke alterer Exemplare be- rrichren, denn ob die kleinen Srucke airklich Jugendformen slnd, erscheinr mir sehr za~eifelhafr; ebensou-enig diirften sie zu einer Gatrung Mojsisovlcs~agehoren, da sie elnen Kiel besirzen und keine Einschnurungen." Er rergleichrilmm. ventanillensis mlt Schloenbachla ~nfira(SOWERBY) und reiht ihn in diese Gattung ein. " Anschrift des Autors: Dip].-Geol. GU~TERGEBHARD, Instirut und &luseum fur Geologie und Palaonro- ]ogle, Sigranstr. IC, D-7400 Tiibingen.